Turning to the drawings, FIG. 1 depicts a prior-art food waste disposer 100, which is described in U.S. Pat. No. 6,854,673. U.S. Pat. No. 6,854,673 is incorporated by reference herein in its entirety. The disposer 100 may be mounted in a well-known manner in the drain opening of a sink using conventional mounting members of the type disclosed in U.S. Pat. No. 3,025,007, which is incorporated herein by reference in its entirety. The disposer includes an upper food conveying section 102, a central grinding section 104 and a variable speed motor section 106. The central grinding section 104 is disposed between the food conveying section 102 and the variable speed motor section 106.
The food conveying section 102 conveys the food waste to the central grinding section 104. The food conveying section 102 includes an inlet housing 108 and a conveying housing 110. The inlet housing 108 forms an inlet at the upper end of the food waste disposer 100 for receiving food waste and water. The inlet housing 108 is attached to the conveying housing 110. A rubber o-ring 112 may be used between the inlet housing 108 and conveying housing 110 to prevent external leaks. A sealant bead may also be used instead of the rubber o-ring 112. The sealant bead is preferably composed of a tacky, malleable material that fills any voids between the inlet housing 108 and the conveying housing 110 and tempers any irregularities in the opposing surfaces of the housings. Some suitable malleable materials for the sealant bead include butyl sealant, silicone sealant, and epoxy.
The conveying housing 110 has an opening 114 to receive a dishwasher inlet 116. The dishwasher inlet 116 is used to pass water from a dishwasher (not shown). The inlet housing 108 and conveying housing 110 may be made of metal or injection-molded plastic. Alternatively, inlet housing 108 and conveying housing 110 may be one unitary piece.
The central grinding section 104 includes a grinding mechanism having a shredder plate assembly 118 and a stationary shredder ring 120. In one embodiment, the shredder plate assembly 118 may include an upper rotating plate 122 and a lower lug support plate 124. The upper rotating plate 122 and lower lug support plate 124 are mounted to a rotatable shaft 126 of the variable speed motor section 106. A portion of the conveying housing 110 encompasses the grinding mechanism. The grinding mechanism shown in FIG. 1 is a fixed lug grinding system. Alternatively, a moveable lug assembly could be used such as that disclosed in U.S. Pat. No. 6,007,006 (Engel et al.), which is incorporated herein in its entirety by reference. The grinding mechanism could alternatively use both a fixed lug assembly and a moveable lug assembly.
The shredder ring 120, which includes a plurality of spaced teeth 128, is fixedly attached to an inner surface of the conveying housing 110 by an interference fit and is preferably composed of stainless steel but may be made of other metallic material such as galvanized steel. As shown in FIG. 1, ramps 129 formed on the inside wall of the housing 110 may also be used to retain the shredder ring 120 in the housing 110.
In the operation of the food waste disposer 100, the food waste delivered by the food conveying section 102 to the grinding section 104 is forced by the lugs 142 on the shredder plate assembly 118 against the teeth 128 of the shredder ring 120. Shredder plate assembly 118 may also include tumbling spikes 144. The sharp edges of the teeth 128 grind or comminute the food waste into particulate matter sufficiently small to pass from above the upper rotating plate 122 to below the plate via gaps between the teeth 128 outside the periphery of the plate 122. Due to gravity and water flow, the particulate matter that passes through the gaps between the teeth 128 drops onto a plastic liner 160 and, along with water entering into the disposer 100 via the inlet to the inlet housing 108, is discharged through a discharge outlet 162 into a tailpipe or drainpipe (not shown). To direct the mixture of particulate matter and water toward the discharge outlet 162, the plastic liner 160 is sloped downward toward the periphery side next to the discharge outlet 162. The discharge outlet 162 may be formed as part of a die-cast upper end bell 164. Alternatively, the discharge outlet 162 may be separately formed from plastic as part of the outer housing of the disposer. The outer surface of the discharge outlet 164 allows a tailpipe or drainpipe to be connected to the discharge outlet 162.
The variable speed motor section 106 includes a switched reluctance machine 180 having a stator 182 and a rotor 184. Stator 182 includes windings 194. The rotor imparts rotational movement to the rotatable shaft 126. The switched reluctance machine 180 is enclosed within the housing 174 extending between the upper and lower end frames 164 and 176. Alternatively, a brushless permanent magnet motor or controlled induction motor could be used. A controller 220 controls switched reluctance machine 180.
Referring back to FIG. 1, as described earlier, the upper end bell 164 separates the grinding section 104 from the variable speed motor section 106. The upper end bell 164 may dissipate the heat generated by the switched reluctance machine 180, prevents particulate matter and water from contacting the switched reluctance machine 180, and directs the mixture of particulate matter and water to the discharge outlet 162.
The plastic liner 160 is attached to the die-cast upper end bell 164 by screws or bolts 166. The upper end bell 164 is attached to the conveying housing 110 by screws or bolts 168. To prevent external leaks, a ring bracket 170 and o-ring or sealer 172 may be used to secure the connection between the conveying housing 110 and the upper end bell 164.
The upper end bell 164 is used to separate the central grinding section 104 and the variable speed motor section 106. The variable speed motor section 106 is housed inside a housing 174 and a lower end frame 176. The housing 174 may be formed from sheet metal and the lower end frame 176 may be formed from stamped metal. The housing 174 and lower end frame 176 are attached to the upper end bell 164 by screws or bolts 178.
To align the rotatable shaft 126 and, at the same time, permit rotation of the rotatable shaft 126 relative to the upper end bell 164, the upper end bell 164 has a central bearing pocket 165 that houses a bearing assembly 200. In one embodiment, the bearing assembly 200 encompasses the rotatable shaft 126 and comprises of a sleeve bearing 202, a sleeve 204, a spacer 205, a rubber seal 206, a slinger 208 and a thrust washer 210. The sleeve bearing 202 is pushed into the smaller portion of the central bearing pocket 165. The sleeve bearing 202 is preferably made of powered metal having lubricating material. The thrust washer 210 is placed on top of the bearing 202. The steel sleeve 204 encompasses the rotatable shaft 126 and is positioned above the thrust washer 210 and sleeve bearing 202. The steel sleeve 204 resides on an upper end portion 127 of the rotatable shaft 126. The upper end portion 127 is shaped as a double D to receive the shredder plate assembly 118. The shredder plate assembly 118 rests on the spacer 205. A bolt 211 is used to hold the shredder plate assembly 118 to the rotatable shaft 126. To keep out debris, rubber seal 206 slides over the steel sleeve 204 and rests in a larger portion of the central bearing pocket 165 of the upper end bell 164. Steel cap or slinger 208 is placed on top of the rubber seal 206.
The bottom of the rotatable shaft 126 is permitted to rotate relative to the lower end frame 176 by the use of bearing assembly 212. The lower bearing assembly 212 includes a housing 214 and a spherical bearing 216. The spherical bearing 216 is preferably made of powdered metal having lubricating material.